Weekly Threat Bulletin: October 21st, 2026
F5, Wednesday, October 21st, 2026
F5 Labs' weekly bulletin covers a telecom MSP breach via FortiManager, the PEERSTITCH injector and other top threats.
F5 Labs' weekly threat bulletin summarizes the top threats of the week.
It leads with threat cluster CL-STA-0954 (UNC5820), which compromised a telecom managed service provider through a FortiManager missing-authentication flaw and stole configurations and keys for over 500 downstream FortiGate firewalls.
The actors then exploited a path traversal flaw to gain root and deploy PEERSTITCH, a memory-resident ARM64 process injector.
The bulletin also covers other actively exploited vulnerabilities and Microsoft's October fixes.